This is what I found:
Common arguments against consistent use of the serial comma:
Use of the comma is inconsistent with conventional practice.
The comma may introduce ambiguity (see examples below).
It is redundant in a simple list, because the and or the or is often meant to serve (by itself) to mark the logical separation between the final two items, unless, of course, the final two items are not truly separate items but are two parts of a compound single item
Also, from the hand out Commas:Conventional Usage
VIII. Do not use a comma between a series of only two. Be careful not to apply the comma
rule to a series of only two elements. Watch out also for those situations where it looks
like you have a series of three elements but it is actually a series of two noun phrases and
a compound verb phrase (if this explanation sounds confusing--see the example).
We brought bread and cheese and read poetry. (Sorry for the Dick-and-Jane sentence, but
"cheese" and "poetry" are not really in a series. No commas for either "and" here.)
So we've established that the conventional usage is to avoid using commas. However, when did the comma started becoming used in a non-conventional way?
I found this:
...and, from being a farmer's drudge and a carrier's lad,...
This is by Dickens, in 1839
Also, in 1516, by Sir Thomas More,:
...and, after those civilities were past which are ordinary for strangers upon their first meeting, we went all to my house; and, entering into the garden...
So although most of the time there were no commas following conjunctions, there are instances when they are used, and its not just a recent thing.